Automatic weighing machine



m 7, 1 41- s. R. HOWARD 2,258,182

AUTOMATIC WEIGHINGMACHINE Filed Feb. 24, 1938 2 Sheets-Sheet 2 Patented Oct. 7, 1941 UNITED STATES PATENT OFFICE AUTOMATIC WEIGHING MACHINE Stanley E. Howard, Milton, Mass, assignor to Pneumatic Scale Corporation, Limited, Quincy, Mass, a. corporation of Massachusetts Application February 24, 1938, Serial No. 192,243

8 Claims.

This invention relates to a packaging machine and more particularly to an automatic weighing machine.

The invention has for an object to provide a novel and improved packaging machine of the type embodying a vibratory feed conduit for feeding a stream of material to be packaged, and in which provision is made for controlling the flow of the material in a manner such as to insure maximum uniformity in the stream.

Another object of the invention is to provide a novel and improved weighing machine of the type embodying a vibratory conveyor for feeding a stream of material to be weighed, and in which provision is made for controlling the flow of the material being introduced into the conveyor from a supply hopper in a manner such that variations in the density of the material caused by variations in the static head of the latter may be absorbed and equalized in a reservoir in the conduit prior to cutting down the size of the stream to the required volume whereby to insure maximum uniformity in the stream discharged from said conveyor irrespective of the variations in the static head of th material in said supply hopper.

A further and more specific object of the invention is to provide a novel and improved weighing machine of the type embodying a vibratory feed conduit for feeding the material to be weighed, and in which provision is made for changing the flow of the material from a, bulk to a drip stream in a manner such as to insure maximum uniformity in the drip stream to enable maximum uniformity in the weights to be obtained.

With these general objects in view and such others as may hereinafter appear, the invention consists in the packaging machine, in weigh ing machine and in the various structures, arrangements and combinations or parts herein after described and particularly defined the claims at the end of this specification.

In the drawings illustrating the preferred 6211- bodiment of the invention, Fig. l is a side elevation of a sufficient portion of a weighing machine embodying the present invention to enable the invention to be understood; Fig. 2 is a detail in view in side elevation illustrating a portion of the mechanism shown in Fig. 1; Figs. 3 and i are detail views in cross-section illustrating the vibratory feeder and the gate in different positions of operation for controlling the stream of material being fed, and Fig. 5 is a wiring-diagram showing the circuit for controllingthe vibration of the feeder.

Heretofore, in prior weighing machines 01 the vibration of the feed conduit from a high rate of vibration during the bull: weighing period of operation to a low rate of vibration during the drip weighing period of operation of the machine. Experience has demonstrated that this type of control for the feed conduit is unsuitable for certain materials, particularly materials which have a tendency to stick together or to form lumpy particles, because during the period when the vibrator was operated at a low rate of vibra tion the material would tend to break ofi, in sections, from the mouth of the conduit and cause a lack of uniformity in the drip stream. It was also found that this type of control would tend to produce a supply of material in the conduit which was variable in depth because the restricted area of the throat of the hopper from which the material emanates-into the conduit would cause the material to be released spasmedically, according to the nature of the material. These disadvantages in the variable rate of vibration for the control of the bulk and drip streams materially interfered with obtaining uniformity in the stream and consequently in the weights produced.

In accordance with the present invention, provision is made for mechanically changing the stream of material being fed from the vibratory conduit during the difierent portions of the weighing operation by a gate, while the conduit 'tiveiy high frequency of vibration in the feed conduit durine both portions of the weighing operation, the material tends to level ch in the conduit and even itself. up to a uniform depth and also to disintegrate any material which may be formed in lumps so that a stream of maximum uniformity is assured. it is also preferred in the illustrated machine to maintain a reservoir of material between the throat of the supply hopper and the gate for reducing the stream whereby the material may be permitted to expand and become loosened before it is discharged from the conduit so that a stream of material of uniform density may be maintained. The provision of a gate at a spaced distance from the hopper throat permits the use of a less restricted opening in the hopper whereby the static head of the material in the hopper may be utilized to maintain a constant and more uniform supply in the conduit. 7

In the illustrated machine and in the following description of the preferred embodiment of the invention, movement of the cam shaft is referred to as a cycle of operation and in the particular machine illustrated, one cycle constituting one half revolution oi the cam shaft causes a relatively small increment of material to be added to bring the bulk load to a predetermined finished weight and another cycle contuting another half revolution of the cam shaft sea a bulk feeding and weighing cycle. The ,tion and operation of the cam shaft in the ove described manner may be accomplished in any usual manner, preferably by a one revolution clutch, not shown, which may be geared to the cam shaft at a ratio of 2 to i so that one volution of the clutch will rotate the cam shaft ii revolution. Suitable connections for operation of the one revolution 611E012 i operation of the well known ghing machine now upon the mar- Vlty into ithcugh, for stration, but one weig" ing unit n, it wiii be understood that the pres v preferably be incorporated in Weighing machine, where n the lies materia each oi the maccnduits iii. The hopper with a suitable adjusting plate M e amounts of material permitted to conduit 52. [is herein shown, the conduit is arranged to be vi- 1 the material through the conduit is illustrated in Fig. l

unections including a thin steel strap d one end, and a second strap 53 mer end is connected to an electrically vibratory motor 28 of any usual or pree. The vibratory unit is mounted ti. extending from the machine 1 provided with suitable shock absorbing washers 24 between it and the bracket 22.

in accordance with the present invention, provision is made for initiating the vibration of the delivery conduit, as will be hereinafter described, to feed the material, and in the illustrated machine the material is fed first through an accumulating chamber 30 and then into a weighing bucket 32 mounted upon one end of a scale beam 34 and provision is made for stopping the vibration of the delivery conduit l2 and for cutting off the supply of material through the hopper 30 by the movement of the scale beam 34 when the scale has made its weight. As herein shown, the hopper 30 comprises a vertical chamber mounted upon a plate 35 secured to the bracket 22 and is provided at its upper end with an oil-- set communicating with the mouth of the conduit l2. A flexible gasket or adapter composed of leather or other suitable material is provided to connect the conduit i2 to the hopper 30 so as to permit vibration of the conduit without effecting vibration of the hopper. The hopper -f: is further provided, at its lower end, with cm the movement of the scale beam are conduit 12 is mounted to be vibrated .54 of a lever loosely mounted upon a shaft 44 journaled in suitable bearings secured to the hopper II. The second arm 54 of the loosely mounted lever is provided with the movable member 40 of any usual or preferred form of electromagnet, indicated generally at 42. The connections for raising the movable member Cl in order to retain the shutters 42, 44 in their open positions during the weighing period include a cam 84 fast on a cam shaft 64, a cooperating roller ll mounted on a cam lever II, a connecting rod 12 and a lever 14 fixed to the shaft 80. A second lever 16 also fixed to the shaft 56 is provided with a bearing surface 88 arranged to engage a stud Bil extending from the arm 58. The shutters are normally held in their closed position by a spring .32, one and of which is secured to the hopper Ill and the other end to the arm 88. Zhe cam lever ill and cam roller 5| comprise one set of three duplicate levers and cam rolls. the upper of which is shown in Fig. All of levers 70 are loosely mounted upon a rocker shait H and each lever is connected to a separate connecting rod as will be hereinafter described. Each lever 10 is "provided with a second arm 13 to which a spring ii is attached in order to hold each roll it against its respective cam.

In the illustrated machine, the shutters 42, 44 are arranged to be opened at the beginning of each weighing cycle and as herein shown, the cam 54 is provided with a second lobe 6! so that the shutters are opened and closed twice during each complete weighing operation. During the operation of the machine, the cam 84 is arranged to raise the movable member 60 into contact with the electromagnet 62, operating to retain the shutters in their open position while the cam advances beyond the high point and comes to rest in this position. Thus the shutters are free to close, through the spring 82, when the electromagnet E2 tie-energized to release the arm 53. As shown in Fig. 5, the electromagnet i2 is wired to a contact member 84 with which a movable contact 88 moved by the end of the scale beam cooperates, so that when the scale beam makes its weight, the contacts 44, ll are opened and the electromagnet is tie-energized.

Provision is made for initiating the vibration of the feeding conduit I2 at the beginning of each cycle of operation and for thereafter, during the remainder of the cycle, permitting the vibration of the feeding conduit to be controlled by the movement of the scale beam. As herein shown. see Lg. 1, the vibration of the material delivery conduit is controlled through a switch which is arranged to be closed by a cam 92 fast on the cam shaft 88. The cam 92 cooperates with one of the rollers 48 carried by one of the levers l0 and is connected to a curved lever 94 by a rod 96. The lever '94 is fixed to a shaft 94 and a second lever I00, provided with a bifurcated end, embraces a vertical rod I02 and is arranged to engage the underside of a collar I03 fixed thereto. The upper end of the vertical rod I0! is slidingly fitted into a swivel connection 104 carried by the switch arm I". A coil spring )6, fitted between the collar i 03 and the swivel connection normally smi'msm .gn time 0 mime cam $2 wanes 'm FESS m 0 K. V J

Du Ling 10b. SE36 1e Viki in S 2 s lersem a posifa'i aration,

tinted upon a stud ward m e 010v 16 nit at? sled ment 9 provi jus M2 1; made for raising the member I56 upwardly, see Fig. 2. in order to free the scale beam for its final load weighing and as herein shown, a hooked member I62, adapted to engage a pin I64 extending from the member I55, is arranged to be raised and lowered by a cam I66 mounted on the cam shaft 66. The connections between the cam I66 and the hooked member I62 include a cooperating roller I68, a bell crank I10, link I12 and a two armed lever I14 pivoted at I76. It will be seen that the cam I66 is designed to permit the tension to be applied to the scale beam during one half revolution and to retain the tension applying members in their raised or ineffective position during the other half revolution.

Provision is made for automatically releasing the weighed load in the receptacle 32 in order to permit the material to flow by gravity through the funnel 280 and into a container I82 supported upon a conveyor I84. As herein shown, see Fig. l, a toggle mechanism, generally indiat normally holds the gate I88 in its closed position through the tension of the spring 590. The gate is arranged to be opened by arm 2'92 which is rocked into engagement wi h a roller Hi4 to release the toggle mechanism. The arm i532 is arranged to be rocked by a cam 29%, fast on the cam shaft 55, through connections including a cooperating roller I98, a bell crank 20D, connecting rod 202 and a lever 2% fast on the rocker shaft 288 upon which the arm 592 is also fast.

From the description thus far, it will be observed that in the operation of the illustrated machine, two separate and distinct weighing operations are performed during each complete operation of the machine and that the bulk weighing operation is performed during the first cycle and the final weighing operation is performed during the second cycle. While provision is made for manually controlling the amplitude of vibration of the material feeding conduit 52 by provision of a rheostat 208 in the circuit, see Fig. 5, the conduit is vibrated during the cycles of operation of the machine at a constant rate and the flow of the material from the conduit is mechanically and positively regulated by the gate $29.

It will also be observed that material may be accumulated in the chamber 38 during the time that the receptacle is being empded. This be preferably accomplished by setting the vibrator switch cam 32 slightly ahead of the cam 8 for opening the shutters so that when the receptacle has completed clumping its load and has returned to weighing position the accumulated load mav released. This action occurs only during the bull; weighing cycle of operation as during the drip feed cycle, the

vibrator switch 90 is controlled by the movement of the arm 58 as above described.

The operation of the machine may be briefly summarized as follows: During the first cycle of the machine the first operation which occurs is the releasing of the pre iously weighed load from the weighing bucket 32 into the package I82 positioned beneath the guide chute I80. Simultaneously therewith the cam 92 operates to close the switch 90 to initiate the vibration of the material feeding conduit I2. The shutters 42, 44 are at this time in their closed position, and during the period when the load is being dumped from the weighing bucket and the scale returned to weighing position, a partial load is accumulated in the hopper 30. At this time the gate I20 is in its raised position to permit the normal or bulk flow of material from the conduit I2 as illustrated in Fig. 4. When the scale beam 34 has returned to weighing position, the slotted member I56 is lowered to permit the spring I52 to apply a tension upon the weighing end of the scale beam and the arm 58 is rocked to open the shutters 42, N and to retain the vibrator switch in its closed position. The arm I08 is now rocked downwardly to permit the switch 90 to be controlled by the arm 58 during the remainder of the cycle. When the scales makes its weight, the arm 58 is released, closing the shutters and stopping the vibratory motor. The machine is now ready to start on its second cycle of operation during which time the spring weight I56 is raised, the plate I28 is rocked to its lowered position as illustrated in Fig. 3 and the arm 58 is reset to start the vibrations and open the shutters. When the scale makes its final load weight a new cycle of operations is initiated.

While the preferred embodiment of the invention has been herein illustrated and described, it will be understood that the invention may be embodied in other forms within the scope of the following claims.

Having thus described the invention, what is claimed is:

1. In a weighing machine of the character described, a control shaft arranged to be operated in successive cycles, a weighing device, a vibratory conveyor for feeding material to said weighing device, means for vibrating the conveyor at a substantially constant rate of vibration sufficiently high to form a bulk stream and greater than is required to form a drip stream, during both bulk and drip feeding cycles, a gate positioned intermediate the ends of the conveyor capable of holding back the major portion of the material to change the size of the stream being discharged from a bulk stream to a drip stream independently of the vibration of the conveyor and to effect a damming of the material behind the gate, and connections between said control shaft and said gate for changing the position of the latter at the beginning of each feeding cycle.

2. In a weighing machine of the character described, a control shaft arranged to be operated in successive cycles, a weighing device, a vibratory conveyor for feeding material to said weighing device, means for vibrating the conveyor at a relatively high rate of vibration, a hopper for supplying material to said conveyor and through which material is delivered in variable quantities in accordance with the static pressure of the material therein, a mechanically operated gate positioned intermediate the ends of said conveyor in the path of the forwardly moving material therein, and spaced a sub stantial distance from a throat of said hopper. said conveyor being vibrated at a rate sufficiently high to produce a bulk stream and greater than required to produce the drip stream. said gate being capable of holding back the major portion of the bulk stream and for partially cutting off a portion of the latter to change it into a drip stream, and connections between said control shaft and said gate for changing the position of the latter at the beginning of each cycle of operation.

3. In a weighing machine of the character described, a control shaft arranged to be oper- .ated in successive cycles, a weighing device, a

vibratory conveyor for feeding material to said weighing device, means for vibrating the conveyor at a relatively high rate of vibration, a hopper for supplying material to said conveyor and through which material is delivered in variable quantities in accordance with the static pressure therein, said hopper being provided with means for adjusting to some extent at least, the size of a bulk stream to be discharged from said conveyor, said conveyor being vibrated at a rate sufiiciently high to produce a bulk stream and greater than required to produce a drip stream, a mechanically operated gate capable of holding back the major portion of the bulk stream and adapted to partially cut off a portion of the latter to change it into a drip stream, and

connections between said control shaft and said gate for changing the position of the latter at the beginning of each cycle of operation.

4. In a weighing machine of the character described, a control shaft arranged to be operated in successive cycles, a weighing device, a vibratory material discharge conduit for feeding material to said weighing device and adapted to be operated at a rate of vibration sufliciently high to form a bulk stream and greater than is required to form a drip stream, during both bulk and drip feeding cycles, a hopper for supplying material to said conduit and through which material is delivered in varying quantities in accordance with the static pressure of the material therein, a mechanically operated gate positioned intermediate the ends of said conduit in the path of the forwardly moving material therein, said gate being capable of holding back the major portion of said material,

and being spaced from the throat of said hopper to form a reservoir for the material to enable the latter to expand and absorb any variation in the flow of the material emanating from said hopper throat whereby a uniform stream of material may be produced when the gate is lowered to cut of! a portion of the bull: stream to change the latter into a drip stream, and connections between said control shaft and said gate for changing the position of the latter at the beginning of each feeding cycle.

5. In a weighing machine of the character described, in combination, means including a control shaft arranged to be operated in successive cycles, a weighing device, a vibratory conveyor for feeding material to said weighing device, means for vibrating the conveyor at relatively high rate of vibration, a hopper for supplying material to said conveyor and through which material is delivered in variable quantities in accordance with the static pressure of the material therein, a gate being positioned intermediate the ends of said conveyor and in the path of the forwardly moving material material discharge conduit for feeding material to said weighing device, means for vibrating the conduit at a relatively high rate of vibration, a hopper for supplying material to said conduit and through which material is deliveredin variable quantities in accordance with the static pressure of the material therein, a gate positioned intermediate the ends of said conduit spaced from said hopper and capable of holding back the major portion of the material for changing the size of the stream to a drip stream independently of change in vibration of the conduit to provide bulk and drip cycles of operation and connections between said control shaft and said gate for changing the position of the latter at the beginning of each cycle of operation, said connections including a cam mounted on said control shaft and means operatively connecting said cam and said gate to increase the size of the stream at the beginning of the bulk cycle of operation and to decrease the size of the stream at the beginning of the drip cycle of operation.

- 7. In a weighing machine of the character described, a control shaft arranged to be operated insuccessive cycles, a weighing device, a vibratory material discharge conduit for feeding material to said weighing device and adapted to be operated at a substantially constant rate of vibration, sufficiently high to form a bulk stream and greater than is required to form a drip stream during both bulk and drip feeding cycles, a hopper for supplying material to said conduit and through which material is delivered in varying quantities in accordance with the static pressure of the material therein, a mechanically operated gate positioned intermediate the ends 'of said conduit in the 'path of the forwardly moving material therein, said gate being capable of holding back the major portion of said material and being spaced from the throat of said hopper to form a reservoir for the material to enable the latter to expand and absorb any variation in the flow of the material emanating from said hopper throat whereby a uniform stream of material may be produced irrespective of changes in the static pressure of the material emanating from said hopper when the gate is lowered to cut off a portion of the bun: stream to change the latter into a drip stream, and connections between said control shaft and said gate for changing the position of the latter at the beginning of each feeding cycle.

8. In a weighing machine of the character described, a control shaft arranged to be operated in successive cycles, a weighing device, a vibratory conveyor for feeding material to said weighing device, means for vibrating the conveyor at a rate of vibration sui'flciently high to form a bulk stream and greater than is required to form a drip stream, during both bulk and drip feeding cycles, a gate positioned intermediate the ends of the conveyor capable of holding back the major portion of the material to change the size of the stream being discharged from a-bulk stream to a drip stream independently of the vibration of the conveyor and to effect a damming of the material behind the gate, and connections between said control shaft and said gate for changing the position of the latter at the beginning of each feeding cycle.

STANLEY R. HOWARD. 

